Assessing Aircraft Noise Conditions Affecting Student Learning–Case Studies (2017) / Chapter Skim
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From page 11... ...
4 Re A team of over the co classroom Hawthorne Figure 6 be As the map approxima they receiv Hawthorne because of (though th schools we Table 1 pre sessions co sults 10 observers w urse of 17 sch observation se . low shows the shows, the Le tely beneath t e noise prima District schoo their position ey are subject re chosen as t sents a break nducted at ea ere employed ool days betw ssions were c locations of t Figure 6. nnox District he extended c rily from arriva ls lie to the so ing, schools in to noise from he study contr down of the to ch study schoo by HMMH to een April 6, 20 onducted at 1 he study scho Locations of S So schools are ve enterlines of r l operations d uth of Lennox this district ar local Hawthor ol group. tal number of l. perform noise 16 and April 2 1 schools, five ols in relation tudy Schools urce: HMMH ry close to the unways 07L/2 ue to the sing , well away fro e not as heavi ne Airport, as classrooms, o measuremen 9, 2016. A tot from the Lenn to Los Angeles in Relation to ends of two r 5R and 07R/25 le‐flow traffic m the extend ly influenced b discussed late bserved aircra ts and collect al of 134 one‐ ox District and International LAX unways at LAX L. As they are configuration ed runway cen y noise from L r)
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From page 12... ...
Chapter 4 – Results 12 Table 1. Study Summary by School School District No. Classrooms No. Aircraft Events No. Sessions Buford Lennox 18 207 5 Felton Lennox 12 120 3 Moffett Lennox 16 179 4 Jefferson Lennox 16 131 4 Dolores Huerta Lennox 11 140 3 York Hawthorne 10 48 3 Eucalyptus Hawthorne 19 82 5 Ramona Hawthorne 12 50 3 Washington Hawthorne 12 57 3 Zela Davis Hawthorne 12 39 3 Kornblum Hawthorne 10 89 3 As shown, approximately equivalent numbers of classrooms were observed in both districts (73 from Lennox and 75 from Hawthorne) , as well as the total number of observation sessions (19 in Lennox and 20 in Hawthorne)
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From page 13... ...
Chapter 4 – Results 13 Table 2. Summary of Observation Sessions by School Session No. Date Time School District No. Classrooms Observed No. Aircraft Events 1 6‐Apr‐16 8:30 AM Buford Lennox 4 51 2 6‐Apr‐16 10:20 AM Buford Lennox 4 47 3 7‐Apr‐16 8:30 AM Buford Lennox 4 46 4 7‐Apr‐16 10:50 AM Buford Lennox 3 42 5 7‐Apr‐16 1:00 PM Buford Lennox 3 21 6 11‐Apr‐16 8:15 AM Felton Lennox 4 45 7 11‐Apr‐16 10:15 AM Felton Lennox 4 43 8 11‐Apr‐16 1:00 PM Felton Lennox 4 32 9 12‐Apr‐16 8:15 AM Moffett Lennox 4 42 10 12‐Apr‐16 10:40 AM Moffett Lennox 4 45 11 13‐Apr‐16 8:15 AM Moffett Lennox 4 47 12 13‐Apr‐16 10:40 AM Moffett Lennox 4 45 13 14‐Apr‐16 12:30 PM Jefferson Lennox 4 41 14 15‐Apr‐16 8:30 AM Dolores Huerta Lennox 3 43 15 15‐Apr‐16 12:45 PM Jefferson Lennox 4 30 16 18‐Apr‐16 8:30 AM Dolores Huerta Lennox 4 47 17 18‐Apr‐16 1:00 PM Jefferson Lennox 4 35 18 19‐Apr‐16 8:30 AM Dolores Huerta Lennox 4 50 19 20‐Apr‐16 8:45 AM York Hawthorne 3 16 20 20‐Apr‐16 1:10 PM York Hawthorne 3 14 21 21‐Apr‐16 8:30 AM York Hawthorne 4 18 22 21‐Apr‐16 1:00 PM Jefferson Lennox 4 25 23 22‐Apr‐16 8:30 AM Eucalyptus Hawthorne 3 10 24 22‐Apr‐16 1:10 PM Eucalyptus Hawthorne 4 25 25 25‐Apr‐16 8:30 AM Eucalyptus Hawthorne 4 20 26 25‐Apr‐16 10:30 AM Eucalyptus Hawthorne 4 17 27 25‐Apr‐16 1:10 PM Eucalyptus Hawthorne 4 10 28 26‐Apr‐16 8:30 AM Ramona Hawthorne 4 18 29 26‐Apr‐16 11:00 AM Ramona Hawthorne 4 18 30 26‐Apr‐16 1:10 PM Ramona Hawthorne 4 14 31 27‐Apr‐16 9:00 AM Washington Hawthorne 4 23 32 27‐Apr‐16 11:00 AM Washington Hawthorne 4 26 33 27‐Apr‐16 12:30 PM Washington Hawthorne 4 8 34 28‐Apr‐16 8:30 AM Zela Davis Hawthorne 4 20 35 28‐Apr‐16 10:30 AM Zela Davis Hawthorne 4 19 36 28‐Apr‐16 12:30 AM Zela Davis Hawthorne 4 0 37 29‐Apr‐16 9:00 AM Kornblum Hawthorne 3 37 38 29‐Apr‐16 11:00 AM Kornblum Hawthorne 3 29 39 29‐Apr‐16 1:00 PM Kornblum Hawthorne 4 23 4.1 Measured Noise Levels The observation team logged and recorded over 1,500 total (outdoor) noise events. For the purposes of this analysis, only events that were determined to be "complete" (i.e., not cut off in the noise monitor recording)
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From page 14... ...
road traffic seconds. Figure 7 pr As is to be breakdown Here again there are c District sch Municipal Table 3 pre These met noise sour , 107 to peop esents a graph expected, the of event sour there are diff onsiderably m ools are a mix Airport. sents a summ rics are cumul ces. le, and 62 to o ical compariso Figure 7 number and f ces by district Figure 8. Obs erences betwe ore in the Len ture of much q ary of noise m ative for each ther sources. T n of complete . Observed O So requency of di is given in Fig erved Outdoo en the two dis nox District th uieter operat etrics calculat school and inc he average du noise events utdoor Noise E urce: HMMH fferent event ure 8 below. r Noise Events tricts: both di an in Hawthor ions from LAX ed for the ent lude noise fro ration of aircr by source. vents by Sou sources varies by Source pe stricts are dom ne. Further, th and general a irety of the me m aircraft, roa aft events wa rce with the study r District inated by airc e aircraft eve viation activity asured data fo d traffic, peop Chapter 4 – R s approximate district. A raft events, bu nts in Hawthor from Hawtho r each school le, and all othe esults 14 ly 46 t ne rne . r
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From page 15... ...
As expecte day LAeq r to 99.2 dBA dBA and th Of note in measured result is th of which is instructed Washingto school gro Since the n sessions ov noise prod Ta d, the Lennox anged from 62 . Contrasted e Lmax ranged this data set is outdoor LAeq e fact that alm covered in as to set up the o n Elementary, unds. The loca oise monitor w erlapped with uced by the ch ble 3. School‐ Scho Bufo Felto Moff Jeffer Dolores H Yor Eucaly Ramo Washin Zela D Kornb District schoo .0 dBA to 68.2 with the Hawt from 82.1 dB Washington E and second hi ost all of the o phalt. In order utdoor noise the only such tion where the Figure 9. Sou as placed nea several reces ildren at play. day LAeq and ol Distr rd Lenn n Lenn ett Lenn son Lenn uerta Lenn k Hawth ptus Hawth na Hawth gton Hawth avis Hawth lum Hawth ls generally sh dBA, and the horne District, A to 96.7 dBA lementary Sch ghest Lmax of utdoor groun to reduce the monitor on a s surface is a sm noise monito Aerial View of rce: Imagery an r the center o s periods, the Lmax for All M ict SchoolLAe ox 68.
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From page 16... ...
Table 4 pre thresholds hour perio School Buford Felton Moffett Jefferson Dolores Hu York Eucalyptus Ramona Washington Zela Davis Kornblum Figure 10 p F The outdo threshold l below. sents a break range from 55 d for the purp Table 4 55 d 31 16 40 69 erta 76 8.
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From page 17... ...
School Buford Felton Moffett Jefferson Dolores Hu York Eucalyptus Ramona Washington Zela Davis Kornblum As the tabl result, as t airport as w This data is 4.2 Mo Radar data daily noise compute d Appendix B For daily m correspond Table 5. 55 d 89 100 53 70 erta 56 59 75 29 97 61 86 e shows, the t he noise level ell as the roa again shown Figur deled Noi containing air metrics for ea aily external L for additiona odeling, opera ing to a schoo Percent of Ou BA 6 % % % % % % % % % % % ime spent abo in the commu d traffic and a graphically in e 11. Percent se Levels craft operatio ch day of the Aeq and Lmax l details)
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From page 18... ...
Chapter 4 – Results 18 For the annual modeling, operations from July 1, 2015 through June 30, 2016 were used to compute both school‐ day and 24‐hour metrics. This date range was chosen to provide a full year's worth of data while at the same time including the date range of the study period. School‐day external LAeq values for each day in the study period are broken out by school and are presented in Table 6 below. A comparison of measured aircraft noise levels to the aircraft noise levels computed using RealContours™ for each day of the study period is given in Table 7 on the following page. Table 6. Modeled Daily Aircraft‐only School‐day External LAeq by School Date Daily LAeq (dBA) Lennox Hawthorne Buford Felton Moffett Jefferson Dolores Huerta York Eucalyptus Ramona Washington Zela Davis Kornblum 6‐Apr‐16 66.8 66.8 58.3 63.0 68.9 49.6 51.6 46.9 47.6 43.8 45.0 7‐Apr‐16 66.9 67.1 58.5 63.3 69.0 49.6 51.6 46.9 47.5 43.8 45.0 11‐Apr‐16 66.4 66.5 58.1 62.7 68.6 49.2 51.1 46.4 47.1 43.4 44.6 12‐Apr‐16 66.1 66.0 57.7 62.3 68.2 49.0 51.0 46.4 47.1 43.4 44.5 13‐Apr‐16 66.4 66.3 58.0 62.5 68.5 49.4 51.4 46.8 47.5 43.8 44.9 14‐Apr‐16 66.6 66.7 58.2 63.0 68.8 49.6 51.6 47.2 47.8 44.2 45.3 15‐Apr‐16 66.3 66.5 58.0 62.7 68.5 50.2 51.2 46.5 47.2 43.5 44.8 18‐Apr‐16 66.0 66.9 57.8 63.0 68.2 49.3 51.3 46.8 47.4 43.7 44.8 19‐Apr‐16 66.6 66.4 58.2 62.7 68.7 49.3 51.1 46.5 47.2 43.5 44.7 20‐Apr‐16 66.7 66.5 58.3 62.8 68.8 49.5 51.5 46.9 47.5 43.8 45.0 21‐Apr‐16 66.9 67.5 58.6 63.7 69.0 49.7 51.7 47.0 47.7 44.0 45.1 22‐Apr‐16 66.1 66.0 57.7 62.3 68.2 49.4 51.5 47.0 47.6 43.9 45.0 25‐Apr‐16 66.2 66.2 57.8 62.5 68.4 49.0 50.9 46.3 47.0 43.3 44.4 26‐Apr‐16 66.2 66.3 57.8 62.6 68.3 49.1 51.1 46.5 47.1 43.4 44.6 27‐Apr‐16 66.0 66.4 57.7 62.6 68.2 49.3 51.6 46.9 47.6 43.8 44.9 28‐Apr‐16 66.7 66.6 58.3 62.9 68.8 49.6 51.7 47.0 47.7 43.9 45.0 29‐Apr‐16 66.5 67.1 58.2 63.2 68.7 49.4 51.4 46.8 47.5 43.8 44.9 Annual*
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From page 19... ...
Chapter 4 – Results 19 Table 7. Comparison of Measured to Modeled 7‐Hour External LAeq Date School Measured LAeq (dBA) Measured Aircraft‐only LAeq (dBA)
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From page 20... ...
Chapter 4 – Results 20 Table 8. Modeled Daily Aircraft‐only School‐day External Lmax by School Date Daily Lmax (dBA) Lennox Hawthorne Buford Felton Moffett Jefferson Dolores Huerta York Eucalyptus Ramona Washington Zela Davis Kornblum 6‐Apr‐ 16 91.0 90.9 79.3 85.3 94.0 67.4 70.9 66.3 67.0 63.0 63.8 7‐Apr‐ 16 90.5 90.4 79.6 85.1 93.4 64.5 68.7 63.4 63.9 59.2 60.1 11‐Apr‐ 16 85.2 89.8 73.6 82.2 88.2 64.5 68.6 63.0 63.9 59.2 60.1 12‐Apr‐ 16 84.9 89.7 73.5 83.3 88.2 64.5 68.6 63.0 63.9 59.2 60.1 13‐Apr‐ 16 85.0 88.3 73.5 81.5 88.2 64.5 68.6 63.4 63.9 59.2 60.1 14‐Apr‐ 16 85.3 89.7 73.4 84.2 88.2 64.5 68.6 63.4 63.9 59.2 60.1 15‐Apr‐ 16 85.0 89.4 73.5 83.9 88.2 77.4 68.6 63.0 63.9 59.2 60.1 18‐Apr‐ 16 85.0 89.7 73.8 83.1 88.0 64.5 68.6 63.4 63.9 59.2 60.1 19‐Apr‐ 16 85.1 84.9 73.4 79.3 88.2 64.5 68.6 63.0 63.9 59.2 60.1 20‐Apr‐ 16 85.4 84.9 73.4 79.5 88.2 64.5 68.6 63.4 63.9 59.2 60.1 21‐Apr‐ 16 85.3 89.7 73.6 83.1 88.2 64.5 68.6 63.4 63.9 59.2 60.1 22‐Apr‐ 16 85.3 86.3 73.5 80.2 88.2 64.5 68.6 63.4 63.9 59.2 60.1 25‐Apr‐ 16 85.1 87.6 74.1 81.2 88.0 64.5 68.6 63.4 63.9 59.2 60.1 26‐Apr‐ 16 84.0 89.7 71.9 83.1 86.7 64.5 68.6 63.0 63.9 59.2 60.1 27‐Apr‐ 16 85.2 89.9 73.5 83.0 88.2 64.5 68.6 63.4 63.9 59.2 60.1 28‐Apr‐ 16 85.0 88.3 73.5 81.3 88.2 64.5 68.6 63.4 63.9 59.2 60.1 29‐Apr‐ 16 85.1 90.8 74.0 83.7 88.2 64.5 68.6 63.4 63.9 59.2 60.1 Annual 85.7 89.9 74.2 88.4 83.7 66.3 68.9 63.4 64.2 59.5 60.6 Note: Values in bold text denote days when observation sessions occurred at a school Table 9 presents the modeled annual average external DNL, external 24‐hour Lmax, and 24‐hour external LAeq, and school‐day external LAeq, using the operations from July 1, 2015 to June 30, 2016. The same location points from Table 8 were used for this modeling.
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From page 21... ...
Chapter 4 – Results 21 Table 9. Modeled Annual Aircraft‐only DNL, 24‐hour Lmax, 24‐hour LAeq, and School‐day LAeq School DNL 24 Hour Lmax 24 Hour LAeq School‐day LAeq Buford 69.7 90.8 65.5 66.6 Felton 70.0 93.1 65.6 66.7 Moffett 61.5 79.9 57.2 58.4 Dolores Huerta 71.4 93.1 67.4 68.6 Jefferson 66.3 87.1 61.9 63.0 York 53.8 69.4 48.4 49.5 Eucalyptus 56.5 69.3 50.5 51.4 Ramona 51.6 64.2 45.7 46.7 Washington 52.3 65.3 46.4 47.4 Zela Davis 48.2 64.3 42.6 43.7 Kornblum 49.3 64.9 43.7 44.9 4.3 Classroom Observations An initial power calculation suggested that 250 classrooms across 21 schools were required in order to be statistically relevant. Unfortunately, due to the unforeseen change in study areas, only 148 classrooms across 11 schools in both the Lennox and Hawthorne school districts were actually observed, as mentioned at the beginning of this chapter. Regardless, there was sufficient data to find significant associations between noise exposure and classroom observations. Table 10 presents the total amount of time each subject type was taught, as well as the mitigation status of each school. The primary academic subjects being taught during the observation sessions were English and math. Table 10. Total Subject Time and Mitigation Status by School School District Mitigated Total Subject Time (minutes) English Math Science Social Studies Other Buford Lennox No 690 577 64 36 151 Felton Lennox Yes 342 333 124 29 106 Moffett Lennox Underground 411 159 169 8 232 Dolores Huerta Lennox Yes 423 337 64 0 63 Jefferson Lennox No 185 1 0 64 191 York Hawthorne No 296 235 13 32 78 Eucalyptus Hawthorne No 217 670 0 0 230 Ramona Hawthorne No 398 164 33 25 365 Washington Hawthorne No 471 109 12 83 109 Zela Davis Hawthorne No 356 90 0 0 61 Kornblum Hawthorne No 49 76 66 123 117 Total 3,837 2,751 544 400 1,702 At the time of this study, only Felton and Dolores Huerta Elementary Schools in the Lennox District had been mitigated by Los Angeles World Airports (LAWA)
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From page 22... ...
Similar to T monitor da School Buford Felton Moffett Jefferson Dolores Hu York Eucalyptus Ramona Washington Zela Davis Kornblum Unlike the consistent should be This data is Because th classrooms removed p able 5, Table ta. Table 1 55 d 58 55 54 58 erta 52 61 69 53 65 54 53 outdoor time across all scho similar betwee presented gr Figure 12. P e presence of , Table 12 pre rior to calcula 11 presents th 1. Percent of BA 6 % % % % % % % % % % % above percent ols and all thr n schools, eve aphically in Fig ercent of Tim the observatio sents the sam tion of the per e percent of ti Indoor Time S Pe 0 dBA 38% 30% 30% 37% 31% 38% 50% 35% 40% 29% 30% ages presente esholds. This i n with varying ure 12. e Above 55 dB n team may h e data from Ta cent time abo me above a gi pent Above a rcent of Time A 65 dBA 17% 9% 11% 16% 12% 16% 26% 16% 16% 14% 14% d in in Table 5 s consistent w outdoor noise A and 70 dBA ave impacted ble 11 with th ve. ven threshold Given Thresho bove Threshold 70 dBA 5% 2% 2% 5% 3% 3% 8% 3% 3% 6% 4% , the values giv ith expectation levels. Threshold by in some way t e first 30 minu calculated fro ld (No Clippin 75 dBA 1% 0% 0% 1% 0% 0% 1% 0% 0% 3% 1% en here are m s, as the indo School (No Cl he attention o tes of each se Chapter 4 – R m the indoor n g)
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From page 23... ...
School Buford Felton Moffett Jefferson Dolores Hu York Eucalyptus Ramona Washington Zela Davis Kornblum This data is F As is show (compare t and most v 4.3.1 St As discusse actions of Student ob grade class Table 13 sh Table 12. P 55 d 61 58 56 63 erta 55 64 73 57 64 60 50 presented gr igure 13. Perc n, even with th o Table 11 an alues increase udent Obs d in Chapter 2 students, logg servations we es were also o ows the brea ercent of Indo BA 6 % % % % % % % % % % % aphically in Fig ent of Time Ab e clipping the d Figure 12) . F by an average ervations each observe ing the times w re primarily pe bserved at Bu kdown of obse or Time Spen Pe 0 dBA 42% 32% 31% 40% 33% 41% 55% 38% 39% 32% 31% ure 13. ove 55 dBA a values remain urther, the diff of 1% (of the d classroom w hen a studen rformed in th ford Elementa rved classroom t Above a Give rcent of Time A 65 dBA 20% 10% 12% 18% 13% 19% 29% 17% 15% 16% 15% nd 70 dBA Thr more or less erences betw total observa as designated t becomes dist ird, fourth, an ry in the Lenn s at each sch n Threshold ( bove Threshold 70 dBA 6% 2% 3% 5% 3% 4% 9% 4% 4% 7% 5% eshold by Sch consistent acr een the clippe tion time at ea an observer w racted as well d fifth grade c ox District. ool by grade.
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From page 24... ...
Chapter 4 – Results 24 Table 13. Grades of Observed Classrooms by School School District Grade Total Second Third Fourth Fifth Buford Lennox 4 5 5 4 18 Felton Lennox 0 4 4 4 12 Moffett Lennox 0 6 5 5 16 Jefferson Lennox 0 6 5 5 16 Dolores Huerta Lennox 0 4 4 3 11 York Hawthorne 0 4 3 3 10 Eucalyptus Hawthorne 0 8 6 5 19 Ramona Hawthorne 0 4 4 4 12 Washington Hawthorne 0 4 4 4 12 Zela Davis Hawthorne 0 4 4 4 12 Kornblum Hawthorne 0 4 3 3 10 Total 4 53 47 44 148 Table 14 presents the total number of minutes students were observed to be either actively learning or distracted at each school as well as the calculated ratio of the time spent distracted to time spent learning. Table 14. Total Time Learning vs. Distracted by School School Total Learning Time (minutes) Total Distracted Time (minutes)
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From page 25... ...
The predo number of includes pr daydreami Of particul day of the low, less th individually noise even recorded a 4.3.2 Te Table 15 p voice, had minant source distraction ev imarily distrac ng. ar interest to t study period. T an 0.1%. The for two minu ts, but if they s a distraction acher Obs resents a summ their voice ma Figure of distraction ents. The seco tions that the his study is th he overall pe reason for this tes at a time, were not being event. ervations ary of the tot sked by extern 14. Student D for students w nd largest sou students caus e fact that the rcentage of dis happening is it is possible th observed at t al number of al noise, or ha istraction So as other stude rce of distract e to themselve re were no ob tractions caus likely methodo at other stude he time when minutes teach d to raise the urces by Coun nts, which ac ions was "othe s, such as play served aircraft ed by other tr logical; since nts were dist it occurred th ers at each sch ir voice while t t counted for 50 r" at 29.2%. T ing with vario noise‐related ansportation n each student w racted by tran en it would no ool used thei eaching. Chapter 4 – R .9% of the tot his category us items and distractions o oise was also as observed sportation rela t have been r normal teach esults 25 al n any very ted ing
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From page 26... ...
Figure 15 p voice) by t Unsurprisi logged tea prevalent o Of note is t Washingto 4.4 Sta Analyses w characteriz Learners (E Teacher vo the onset o across the resents a brea he total observ ngly the norma cher observati f the speaking he fact that te n Elementary, tistical An ere performed ed to have hig LL)
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From page 27... ...
Chapter 4 – Results 27 While student distraction was observed in the classrooms, the frequency of events of this type was very low, and as such no analyses were performed on them. Simultaneous with classroom observations, acute noise monitoring was undertaken within (internal) and outside (external)
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From page 28... ...
teacher vo seconds be Interesting seem to al association before. Th noise expo the mean L 30 second 4.4.2 A O Ev Similar to T dBA for LA internal an Internal/E Inter Inter Inter Inter Exter Exter Exter Exter Internal LA events, bu internal LA being obse The differe indicate th contrasts w Internal TA external TA associated There is co external LA the hypoth metric tim 4.4.3 A Another w classroom ice‐masking ev fore increased ly, for all these ter the strengt to the metric is may be acco sure over thes Aeq ranges ar metrics. cute Noise nset of Tea ents able 16, Table eq and percen d external noi Table 17. xternal nal nal nal nal nal nal nal nal eq 1 second, 5 t external LAeq eq 1 second, 5 rved by 5‐9%.
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From page 29... ...
observed i TA metrics in a classro Internal NA NA55, NA7 1 voice‐ma 1 noise eve by 10%; an External N events, bu associated The lack of probably in the data. Contrastin events per voice‐mask 4.4.4 A Association classroom dBA, falling 80 dBA. No sessions, 2 Internal TA external TA by 12% and raising eve risk for 1 v across the Internal an increase in observing event. The raising eve A 1 noise e increase in and NA70 Increas increas internal the risk n 10% of the s were not sign om session. 60 and NA65 0, NA75 and N sking events b nt increase in d 2 or more vo A55, NA60, NA t NA75 and NA with a 11‐15% associations f dicative of th g the NA and T se, rather tha ing events. cute Noise s of the NA m session were a to less than 1 teacher voice or more even 55, TA60 and 55, TA60 and for 2 or more nt by 17% and oice‐raising ev increasing noi d external NA internal NA55 0‐1 voice‐raisin higher interna nts (33% and 1 vent increase the risk for ob was associated es in dBA lev es in numbe and extern of voice-rais essions, and 3 ificantly assoc showed signif A80 did not. A y 9%; 1 to 2 vo internal NA60 ice‐masking e 65 and NA70 80 did not. A increase in th or internal NA e few events o A metric resu n the time spe Exposure a etrics and TA lso examined at 80 dBA. Th ‐raising event ts were observ TA65 were ass TA65 were no voice‐raising for 2 or more ent by 24% an se metrics, it a metrics showe , NA60, NA65, g events, and l NA metrics ( 13%) than the in external NA serving 0‐1 vo with a 9‐10% el for intern r of events f al NA metric ing events.
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From page 30... ...
Contrastin associated showed as raising eve than the ti 4.4.5 C The model A 1 dBA inc the risk for The data s masking ev be associat voice‐mask masking ev The data s Using our e with a 130 events. 4.4.6 C Table 18 a internal no of the outc the interna association events. All of internal teacher vo noise metr teacher vo For the nu show assoc voice‐raisin with teach External TA events. Int events. To some ex external no g the findings with voice‐rai sociations with nts, and also s me above. hronic Airc ed annual exte rease in exter observing mo uggest a dose‐ ents. Using es ed with an 80 ing events. A ents by 13% a uggest a dose‐ stimates, we % increase in r omparison nd Table 19 su ise metrics an omes, respect l and external s with the ons of the interna TA55, showed ice‐raising eve ics showed as ice‐raising eve mber of event iations with t g. External TA er voice‐mask metrics show ernal TA metri tent, we migh ise metrics, g for the NA and sing events, ye voice‐raising uggest that in raft Noise E rnal LAeq 24 nal LAeq 24 ho re than 2 voic response relat timates, it wa % increase in r 1 dBA increase nd the risk for response relat calculate that isk for 0‐1 voic of Findings mmarize wher d external noi ively. For the noise metrics et of teacher v l noise metrics associations w nts, yet none sociations with nts. s, both interna eacher voice‐m metrics show ing and teache ed no associa cs showed ass t expect to ob iven the high c TA metrics, w t for the exter events. These terms of exter xposure hour for each s urs increased e‐masking eve ionship betwe s calculated th isk for 1‐2 voi in external LA observing mo ionship betwe a 10dBA increa e‐raising even Across No e statistically se metrics, for onset of event examined sho oice‐masking , with the exce ith the onset of the externa the onset of l and external asking and te ed no associat r voice‐raising tions with num ociations with serve similar a orrelations be e observe tha nal noise met findings confi nal noise that chool ranged the risk for ob nts by 17%. en annual ext at a 10 dBA in ce‐masking ev eq 24 hours in re than 1 voic en annual ext se in annual e ts and a 210% ise Metrics significant asso each s, all wed ption of l NA acher ions . ber of teache the number o ssociations of tween noise m Th e st in w h t internal TA a rics only exter rm the import the number o from 42.6 dBA serving 1‐2 vo ernal LAeq 24 crease in annu ents and a 170 creased the r e‐masking eve ernal LAeq and xternal LAeq 2 increase in ris ciations were r masking eve f voice‐raising all the interna etrics. e link betw xposure and udy team e crease in an ould be ass igher risk for nd internal NA nal NA and no ance of intern f events may b to 67.4 dBA i ice‐masking e hours and the al external LA % increase in isk for observi nt by 21%. the risk of vo 4 hours woul k for more th observed bet nts or teacher events but no l noise metric een chronic classroom stimates tha nual extern ociated with voice-raisin Chapter 4 – R were both t external TA al noise for vo e more impor n the data sam vents by 8% a risk of voice‐ eq 24 hours w risk for more t ng 0‐1 voice‐ ice‐raising eve d be associate an 1 voice‐rais ween each of voice‐raising t voice‐maskin s and of all the aircraft nois behavior: Th t a 10dBA al LAeq 24 H significantl g events. esults 30 ice‐ tant ple. nd ould han 2 nts. d ing the g e e rs y
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From page 31... ...
Chapter 4 – Results 31 Table 18. Summary of Associations Observed Between Internal Noise Metrics and Key Outcomes Onset of the Event Number of the Event Observed Teacher Voice‐ masking Teacher Voice‐ raising Student Distraction Teacher Voice‐ masking Teacher Voice‐ raising Student Distraction Short‐Time Period Metrics LAeq 1 Second X X LAeq 5 Second X X LAeq 10 Second X X LAeq 30 Second X X TA55 5 Second X X TA55 10 Second X X TA55 30 Second X X TA60 5 Second X X TA60 10 Second X X TA60 30 Second X X TA65 5 Second X X TA65 10 Second X X TA65 30 Second X X Entire Test‐Session Metrics NA55 X X NA60 X X NA65 X X TA55 X X TA60 X X TA65 X X
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From page 32... ...
Chapter 4 – Results 32 Table 19. Summary of Associations Observed Between External Noise Metrics and Key Outcomes Onset of the Event Number of the Event Observed Teacher Voice‐ masking Teacher Voice‐ raising Student Distraction Teacher Voice‐ masking Teacher Voice‐ raising Student Distraction Short‐Time Period Metrics LAeq 1 Second X X LAeq 5 Second X X LAeq 10 Second X X LAeq 30 Second X X TA55 5 Second X X TA55 10 Second X X TA55 30 Second X X TA60 5 Second X X TA60 10 Second X X TA60 30 Second X X TA65 5 Second X X TA65 10 Second X X TA65 30 Second X X Entire Test‐Session Metrics NA55 X X NA60 X X NA65 X X TA55 X X TA60 X X TA65 X X Annual LAeq for Aircraft Noise X X 4.5 Teacher Surveys The teacher noise survey assessed a range of demographic factors, perceived health, noise annoyance, perceived interference of noise on school activities, and the perceived impact of aircraft noise on student and teacher behaviors. A total of 105 teachers from nine of the 11 observed schools participated in the teacher survey. A summary of participant data is given in Table 20.
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From page 33... ...
Survey par accounted representa should not Survey res were from 55 dBA LAe distributio Variable Gender Male Female Grade Taught Kindergarten Grade 1 Grade 2 Grade 3 Grade 4 Grade 5 Age Years Teaching ticipation varie for 38% of the tiveness of th be thought of ults were linke schools expos q. There were n of participan Figure 16 Tab Percent 12.4 83.7 7.6 9.5 8.6 23.8 26.7 23.8 d by school. T total data set e teacher surv as representa d to modeled ed to less than no participan ts by their res . Number of P le 20. Summa Numbe 104 13 91 105 8 10 9 25 28 25 105 105 wo of the stud . This differen ey and may int tive of teache external LAeq 50 dBA LAeq ts from schoo pective school articipants by ry of Survey R r Avera 45 18 y schools pro ce in participa roduce bias in r attitudes to n values for eac , and the rema ls in the 50‐54 's LAeq. Aircraft‐only E espondents ge StanDevi 9 9 duced no part tion necessari to the finding oise in these h school. Appr ining 59% wer .9 dBA LAeq ra xternal LAeq dard ation Missi 1 0 .0 0 .5 0 icipants, while ly influences th s. For this reas districts. oximately 41% e from school nge. Figure 16 24 hours at Sc Chapter 4 – R ng data % (n)
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From page 34... ...
4.5.1 P One of the perception with an av according t linear regr differences exposed to Figure 17 p Another po failures in of 100) in o differences school, or t responden Figure 18 p erceived H survey items of stress in th erage score of o demograph ession, the diff were found w LAeq above 5 resents the di rtion of the su perception, m ur sample, wi in scores whe he school exte ts typically sco resents the CF ealth completed by e past month.
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From page 35... ...
4.5.2 N A portion o occurrence reported s hearing air when teac noise when There were found that to report a 79% of res 17.1% repo annoyance annoyed b Of particip very annoy oise Annoy f the survey q as well as the ometimes, oft craft noise. Al hing, however teaching. no difference teachers from ircraft noise a pondents repo rted always h , and 51.4% re y road traffic. ants respondin ed by noise fr C Complete Da Missing Data Missing Data Missing all 2 ance uestions focus effects of noi en or always h most two‐third 25.4% of resp s in aircraft no schools that a nnoyance at sc rted sometim earing road tra ported slight o g to question om other stud Figure 18. Dis Table 22. C FQ Data Availab ta for 25 Quest for 1 Question for 2 Questions 5 Questions ed on noise a se events from earing aircraft s of the respo ondents repor ise annoyanc re exposed to hool than tea es, often, or a ffic. Of these, r moderate a s on student‐c ents, compare tribution of CF FQ Data Avail le ions nnoyance and aircraft, road noise around ndents report ted being sligh e levels based 55 dBA exter chers from sch lways hearing 41.9% of resp nnoyance. The aused noise, 4 d with 47.8% Q Scores ability N(%)
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From page 36... ...
Chapter 4 – Results 36 4.5.3 Noise Interference with School Activities Another section of the survey asked teachers about how noise affects classroom activities, and most reported some interference from aircraft noise. 53% of respondents felt that aircraft noise interfered with communication between teachers and students and with students' attention, 46% felt that aircraft noise interfered with students' performance, and 45% felt that aircraft noise interfered with the quality of students' work. In comparison, 57% and 56% of the sample, respectively, felt that road traffic noise sometimes, often or always interfered with students' attention and students' concentration. 49% of the sample felt that road traffic noise interfered with communication between teachers and students, 34.3% felt that road traffic noise interfered with the students' performance, and 31.9% felt it interfered with the quality of students' work. Overall, the percent reporting interference from aircraft noise and road traffic noise was similar for communication between teachers and students, students' attention, and students' concentration. More teachers reported aircraft noise interfering with students' performance and the quality of students' work, compared with reports for road traffic noise. There were strong associations between external LAeq at school and reports of aircraft noise sometimes, often or always interfering with school activities. Teachers from schools with external LAeq above 55 dBA were 13 times more likely to report interference with communication; nine times more likely to report interference with students' attention; 15 times more likely to report interference with students' concentration; 11 times more likely to report interference with students' performance; and 14 times more likely to report interference with the quality of students' work. 4.5.4 Impact of Noise on Student and Teacher Behavior Over half (51.4%) of respondents reported that aircraft noise caused students to lose concentration, and 26.4% felt that it caused students to chat and talk, however few teachers reported aircraft noise causing students to fidget and misbehave. 33.3% of teachers reported stopping speaking and 29.5% reported raising their voice when exposed to aircraft noise, while 11.4% reported doing nothing or ignoring the students' change in behavior. Teachers from schools with external LAeq above 55 dBA were twice as likely to report raising their voice compared with teachers from schools with external LAeq below 50 dBA, but this association became non‐significant after adjustment for age, gender, grade taught, and years teaching in school. Teachers from schools with external LAeq above 55 dBA were four to five times as likely to report stopping speaking compared with teachers from schools with external LAeq below 50 dBA. Over half of respondents (50.5%)
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